Final answer:
Newborns can lose heat through convection, radiation, conduction, and evaporation; urination is not a direct mode of heat loss for thermoregulation.
Step-by-step explanation:
The various modes of heat loss in the newborn are convection, radiation, conduction, and evaporation. Among the options provided, perspiration is a form of evaporation and is a valid mode, while urination is not considered a direct mode of heat loss in terms of thermoregulation. Therefore, modes 1, 2, 3, and 4 are correct mechanisms through which newborns can lose heat.
Newborns can lose heat through conduction when they come into direct contact with colder surfaces, through convection when cooler air currents carry away body heat, through radiation when heat is emitted as infrared radiation without direct contact, and through evaporation when sweat on the skin surface evaporates, taking heat away with the moisture.